President Bongo has been in power since 1967
In Gabon, votes have been cast in the first round of parliamentary elections with reports suggesting the turnout was low in at least some parts of the country.
The elections appear to have passed off without major incident apart from a number of disturbances in the south of the country where there is strong opposition to President Omar Bongo's Gabonese Democratic Party (PDG).
Responding to reports of ballot boxes being burned in the southern towns of Moabi, Ndend and Mbigou, he warned that opposition leader Pierre Mamboundou would be liable for prosecution if it was shown that he was behind the incidents.
Mr Mambundo's party, the Union of Gabonese People, has denounced the elections as being stage-managed and fraudulent.
He lost to Mr Bongo in Gabon's last presidential election three years ago, winning just 17% of the national vote.
Having reluctantly introduced a multi-party system in 1990, Mr Bongo has allowed the opposition little room for manoeuvre, and he and the PDG have won a series of resounding election victories.
Mr Bongo's political tactics have brought mild rebukes from watchdogs outside the country, but Gabon's leader has rarely faced the kind of sustained attacks directed at some of his neighbours.
He has helped deflect criticism by presenting himself as a regional peacemaker, mediating on occasion in the conflicts in Angola and the Democratic Republic of Congo - though without any notable success.